A halogen incandescent lamp of this type is disclosed in WO 96/05610 Al for example. This publication describes a two-filament halogen incandescent lamp for vehicle headlights, especially an H4 lamp with two filaments for generating low beam or high beam.
In accordance with statutory regulations, such as ECE Regulation 37 or SAE for example, the low beam filament and high beam filament of a two-filament halogen incandescent lamp of type H4, H13 or HB2, which are designed for use at a nominal on-board network voltage of 12 volts, at a test voltage of 13.2 volts (for H4 and H13 lamps) or 12.8 volts (for HB2 lamps), generate a luminous flux in accordance with values shown in Table 1 below.
TABLE 1Luminous flux of theLuminous flux of theLamp typelow beam filamenthigh beam filamentH4 lamp1000 lm ± 15%1650 lm ± 15%H13 lamp1100 lm ± 15%1700 lm ± 15%HB2 lamp 910 lm ± 10%1500 lm ± 10%
The electrical power consumption of the low beam filament of the H4, H13 and the HB2 lamp amounts to 55 watts at 12 volts in each case. The electric power consumption of the high-beam filament of the H4, H13 and HB2 lamp amounts to 60 watts at 12 volts in each case.
In addition single-filament halogen incandescent lamps for vehicle headlights are known which are able to be used as a light source in a low beam headlight or in a high beam headlight. Examples of such single-filament halogen incandescent lamps are H1, H3, H7 and H11 lamps.
In accordance with ECE Regulation 37 the filament of an H1, H3 H7 or H11 Lamp, which is designed for operation at an on-board network voltage of nominally 12 volts, at a test voltage of 13.2 volts, generates a luminous flux in accordance with values shown in Table 2 below.
TABLE 2Lamp typeLuminous fluxHI lamp1550 lm ± 15%H3 lamp1450 lm ± 15%H7 lamp1500 lm ± 10%H11 lamp1350 lm ± 10%
These single-filament lamps of type H1, H3, H7 or H11 each have an electrical power consumption of nominally 55 watts.
For vehicles which do not possess daytime running lights the power sources of the low beam headlights are normally used to generate a daytime running light or an always-on running light in countries in which driving with the lights on during the day is a requirement. The conventional halogen incandescent lamps listed above are however not designed in respect of their electrical power consumption and service life for use as always-on driving lights or daytime running lights.